5. How to find all of the available DNS records of a domain?

6. How to check a DNS record using of a specific DNS Server?

7. How to find the Reverse DNS Lookup (i.e. to resolve DNS record for an IP address) ?

Command line:
$ nslookup 8.8.8.8

8. How to change the DNS Server port number for the connection with DNS Server?

Command line:
$ nslookup -port=56 example.com

** if DNS server is listing on alternative port

9.How to set the timeout interval for a reply for DNS lookup query?

Command line:

$ nslookup -timeout=10 example.com

10. How to enable debug mode for DNS lookup query?

Debug mode provides important and detailed information both for the question and for the received answer.

Command line:
$ nslookup -debug example.com

Note:

Authoritative answer – This is the answer that originates from the DNS Server which has the information about the zone file.Non-autoritative answer – When a nameserver is not in the list for the domain you did a lookup on.DNS Default port – By default, the DNS servers use port 53.

It’s by design the IP addresses are unreadable in the database. The “Blacklist Management” tab in the cPHulk interface allows you to remove an IP address from the interface. You can also unblock an IP address from the iptables block out with a command such as:

You can not get access to your vmWare instance through VMWare vShpere client or SSH shell access because of your root account on VMWare EXSI (v6.x or higher) is locked out by too many failed login attempts. The only way to unlock is to do it through DCUI console-> ESXI Shell.

Resolution:

First of all we need to enable vmWare EXSI Shell, vmWare EXSI Shell is disabled in default (vmWare 5+). If you did not enable EXSI shell after vmWare EXSI installation on your server, you have to enable EXSI Shell Access using direct console interface.